1. Field of Invention
The present invention relates to an integrated circuit structure and manufacturing methods thereof. More particularly, the present invention relates to an integrated circuit structure comprising a Schottky diode and manufacturing methods thereof.
2. Description of Related Art
The Schottky diode is a rectifying device and is composed of a lightly doped semiconductor layer and a metal layer thereon. As a power rectifying device, the Schottky diode has been widely applied to various high speed electric power switches such as power supply switches, motor control drives, telecommunication switches, and switches for factory automation and electronic automation.
However, with the gradually reduced line width of the device, tungsten metal of superior trench filling ability is used to form the contact window during the back process of an integrated circuit. The fabrication of the Schottky diode cannot be integrated with the process of the tungsten contact window and the Schottky diode is usually formed on another chip. Therefore, extra layout designs or assembly are required to integrate the Schottky diode with the integrated circuit having interconnection lines. In this case, the cost of designs and assembly is increased, and the integrity of the device is adversely influenced.
Furthermore, since the Schottky diode achieves rectification by utilizing the work function difference between the lightly doped semiconductor layer and the metal layer thereon, the metal layer must be formed of a low-resistance metal. Otherwise, the efficiency of the Schottky diode will be degraded, and the entire electrical property of the product will be adversely influenced.